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Novel high-resolution DOA estimation using subspace projection method

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The Journal of China Universities of Posts and Telecommunications 2012年第4期19卷 110-116页

作者： SI Wei-jian lan xiao-yu ZOU Yan College of Information and Communication Engineering Harbin Engineering University Harbin 150001 China No. 91404 Army Qinhuangdao 066000 China

The performance of multiple signal classification （MUSIC） algorithm with regard to solving closely spaced direction of arrivals （DOAs） depends strongly upon the signal-to-noise ratio （SNR） and snapshots. In order to solve this problem, a method by reconstructing the spatial spectrum function with both noise subspace and signal subspace is presented in this paper. The key idea is to apply the full information contained in covariance matrix and change the projection weights of steering vector on the noise and signal subspace by their revised eigenvalues, respectively. Comparing with the MUSIC algorithm, it does not increase any computational complexity either, and remarkably, it has the advantages of simultaneously reducing noise and keeping the high-resolution ability under low SNR and small sample sized scenarios. Simulation and experiment results are included to demonstrate the superior performance of the proposed algorithm.

关键词： direction &arrival (DOA) multiple signal classification low SNR resolution subspace projection

2D SAXS/WAXD ANALYSIS OF PAN CARBON FIBER MICROSTRUCTURE IN ORGANIC/INORGANIC TRANSFORMATION

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Chinese Journal of Polymer Science 2013年第5期31卷 823-832页

作者： Cai-zhen Zhu xiao-lan yu xiao-fang Liu yun-zen Mao Rui-gang Liu 赵宁 xiao-li Zhang 徐坚 Beijing National Laboratory for Molecular Sciences Laboratory of Polymer Physics and ChemistryInstitute of ChemistryChinese Academy of Sciences ShenZhen Key Laboratory of Functional Polymer College of Chemistry and Chemical EngineeringShenzhen University College of Materials Science and Engineering Donghua University

Structure of PAN fibers during pre-oxidation and carbonization was studied using two dimensional small angle X-ray scattering/wide angle X-ray diffraction （2D SAXS/WAXD）. The SAXS results show that during pre-oxidation between 180 ℃ and 275 ℃, the volume content of microvoids increases with the temperature increasing, which may be one of reasons for the decrease of tensile strength ofpre-oxidized fibers. 253 ℃ was the critical transition temperature, the length, diameter, aspect ratio and orientation distribution of microvoids increased with temperature before this temperature and decreased after this temperature. After the high temperature carbonization, lots of spindly microvoids formed. WAXD patterns demonstrate that the crystallite size of PAN fibers first increased before 230 ℃ and then decreased with the increase of temperature during the pre-oxidation. The diffraction peak of PAN fibers at 2θ ≈ 17°almost disappeared at the end of pre- oxidation while the diffraction peak of aromatic structure at 2θ ≈ 25° appeared at 253 ℃. During carbonization, the peak intensity at 2θ ≈ 25° increased apparently due to the formation of graphite structure. The results obtained give a deep understanding of the microstrncture development in the PAN fibers during pre-oxidation and carbonization, which is important for the preparation of high performance carbon fibers.

关键词： Polyacrylonitrile Pre-oxidation Carbonization SAXS/WAXD Microstructure.

Role of in vitamin D in irritable bowel syndrome

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World Journal of Clinical Cases 2023年第12期11卷 2677-2683页

作者： xiao-lan yu Qi-Qi Wu Lian-Ping He Yong-Feng Zheng School of Medicine Taizhou UniversityJiaojiang 318000Zhejiang ProvinceChina Department of Anesthesiology Affiliated People’s Hospital of Jiangsu UniversityZhenjiang 212002Jiangsu ProvinceChina

Irritable bowel syndrome(IBS)is a common chronic functional gastrointestinal disorder affecting 10%-22%of *** development is closely related to the gut microbiota,and the inflammatory and immune responses triggered by the gut microbiota can lead to *** D(VD)effectively treats IBS with fewer side effects by improving gut microbiota,immune regulation,and anti-inflammatory *** the future,it is necessary to carry out epidemiological studies on the relationship between VD and IBS,clinical studies on the efficacy of supplementing VD to improve IBS,and animal studies on the mechanism of VD improving ***,this paper discussed the relationship between VD and IBS.

关键词： Irritable bowel syndrome Vitamin D Gut microbiota Immune response Mental status

Three-stage niobium mineralization at Bayan Obo, China

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National Science Review 2024年第4期11卷 102-110页

作者： Yan yu Yang Li yu Liu xiao-xiao Ling Li-Guang Wu Li Yang lan Yang Bo Yang Yong-Gang Zhao Xian-Hua Li State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences College of Earth and Planetary Science University of Chinese Academy of Sciences Ministry of Education Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking University Mining Research Institute Baotou Iron and Steel(Group) Co.LTD State Key Laboratory of Baiyunobo Rare Earth Resource Research and Comprehensive Utilization

The Chinese Bayan Obo deposit is a world-class rare earth element(REE) deposit with considerable niobium(Nb) and iron(Fe) resources. A complete genetic understanding on all metals is fundamental for establishing genetic models at Bayan Obo. With extensive research being focused on REE enrichment, the timing and controls of Nb enrichment remain unresolved at Bayan Obo, which is mainly due to the challenges in dating, i.e. multistage thermal events, fine-grained minerals with complex textures and the rare occurrence of uranium-enriched minerals with mature dating methods. Based on robust geological and petrographic frameworks, here we conducted ion probe uranium-lead(U-Pb) dating of ferrocolumbite to unravel the timing, hence the genesis of Nb mineralization. Three types of hydrothermal ferrocolumbites—key Nb-bearing minerals—are identified based on their textures and mineral assemblages. They yield U-Pb ages of 1312 ± 47 Ma(n = 99), 438 ± 7 Ma(n = 93), and 268 ± 5 Ma(n = 19), respectively. In line with deposit geology, we tentatively link the first, second and third stage Nb mineralization to Mesoproterozoic carbonatite magmatism, ubiquitous early Paleozoic hydrothermal activity, and Permian granitic magmatism, respectively. While quantifying the contribution of metal endowment from each stage requires further investigation, our new dates highlight that multi-stage mineralization is critical for Nb enrichment at Bayan Obo, which may also have implications for the enrichment mechanism of Nb in REE deposits in general.

关键词： niobium mineralization U-Pb dating ferrocolumbite Bayan Obo

CONVERGENCE OF MODIFIED TRUNCATED EULER-MARUYAMA METHOD FOR STOCHASTIC DIFFERENTIAL EQUATIONS WITH HOLDER DIFFUSION COEFFICIENTS

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Journal of Computational Mathematics 2024年第4期42卷 1109-1123页

作者： Guangqiang lan yu Jiang College of Mathematics and Physics Beijing University of Chemical TechnologyBeijing 100029China

Convergence of modified truncated Euler-Maruyama(MTEM)method for stochastic differential equations(SDEs)with(1/2+α)-Holder continuous diffusion coefficients are investigated in this *** prove that the MTEM method for... 详细信息

关键词： Stochastic differential equations Modified truncated Euler-Maruyama method Strong convergence One-sided Lipschitz Holder continuous

Different nutrient compositions in diet and taking hypoglycemic drugs can modulate gut microbial flora

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World Journal of Diabetes 2022年第9期13卷 799-801页

作者： Zi-Jun Lin Qiong-Wen Zhang xiao-lan yu Bo Zhou Chang-Wei Liu Lian-Ping He School of Medicine Taizhou UniversityJiaojiang 318000Zhejiang ProvinceChina Children’s Hospital of Nanjing Medical University Nanjing 210008Jiangsu ProvinceChina

The diet structure of diabetic patients is different from that of normal *** patients also need to take hypoglycemic drugs to regulate blood *** dieting and drugs affect the gut microbiota of diabetic *** this letter,we discuss that different dietary patterns and the use of hypoglycemic agents may have an impact on changes in gut microbiota in diabetic patients.

关键词： Diabetic patients Gut microbiota Hypoglycemic drugs

Poly(3-hexylthio) thiophene Field-effect Transistor Device Performance: Impact of the Content of Hexylthio Side Chain on Backbone

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Chinese Journal of Polymer Science 2024年第1期42卷 14-23,I0005页

作者： Hao-yu Liu Lian-He Han Ling-Wei Kong Li-Ping Zhu xiao-lan Qiao Mei-Fang Zhu State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Regioregular poly(3-hexylthio)thiopene(P3HTT) has emerged tremendous potential in organic electronic applications due to the strong noncovalent interactions from the sulfur atom linked to thiophene. However, P3HTT generally exhibits low charge mobility mostly due to poor solution processability attributed to dense arrangement of hexylthio side chain in polymer, which led to strong noncovalent interactions among sulfur atoms. To balance the nonvalent interaction and aggregation for P3HTT, herein, we systematically study the effect of hexylthio side chain content in polymer backbone on the structure and properties. A series of regioregular P3HTT-based homopolymers(P3HTT, P3HTT-50,P3HTT-33 and P3HTT-25) were prepared via Kumada catalyst transfer polycondensation method from a set of mono-, bi-, ter-and quarterthiophenes containing different contents of hexylthio side chain. The DFT calculation shows the planarity of polymers backbone could be improved through reducing the density of hexylthio side chain in polymer mainchain. And significant changes in their crystallinity, aggregation and optical properties were observed with the content of hexylthio side chain reducing. The P3HTT-33 displayed the highest field-effect transistor hole mobility of 2.83×10^(-2) cm^(2)·V^(-1)·s^(-1) resulting from a balance between the crystallinity and planarity. This study demonstrates modulating the content of hexylthio side chain in P3HTT is an effective strategy to optimize the opto-electronic properties of polymer obtaining excellent semiconductor device performance.

关键词： Conjugated polymer Polythiophene Noncovalent interaction Molecular aggregation Organic field-effect transistor

Cross section determination of^(27)Al(n,2n)^(26)Al reaction induced by 14-MeV neutrons uniting with D-T neutron activation and AMS techniques

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Nuclear Science and Techniques 2024年第6期35卷 78-89页

作者： Xian-Lin Yang Chang-Lin lan yu-Ting Wei Yi Zhang Gong Jiang Bo Xie yu Liu Hong-Tao Shen xiao-Jun Sun School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China MOE Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology Guangxi Normal UniversityGuilin 541004China

Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great *** address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion *** the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He ***^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of *** neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb *** measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature *** newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental *** obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.

关键词： 14-MeV neutron ^(27)Al(n,2n)^(26)Al Cross section AMS

A Strong,Tough,and Self-Healing Strengthening Thioctic Acid-based Elastomer for Highly Reliable Flexible Strain Sensor

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Chinese Journal of Polymer Science 2024年第10期42卷 1610-1618,I0016页

作者： Xin-yu Chen yu-Bing Fu Xue-Ling Yan lan Liu School of Materials Science and Engineering Key Lab of Guangdong Province for High Property and Functional Polymer MaterialsSouth China University of TechnologyGuangzhou510641China

Elastomers with high strength and toughness,excellent self-healing properties,and biocompatibility have broad application prospects in wearable electronics and other fields,but preparing it remains a *** this work,we propose a highly adaptable strategy by introducing the small molecule crosslinking agent of triethanolamine(TEA)to the poly(thioctic acid)(PTA)chains and preparing the PAx Ey elastomers using a simple synthesis *** strategy stabilizes the PTA chains by constructing multiple non-covalent cross-linked dynamic networks,endowing materials with excellent strength and toughness(tensile strength of 288 kPa,toughness of 278.2 kJ/m3),admirable self-healing properties(self-healing efficiency of 121.6%within 7 h at 70℃),and good *** PAx Ey elastomers can also be combined with MWNTs to become flexible strain sensors,which can be used to monitor human joint movements with high sensitivity,repeatable responses,and stability.

关键词： Thioctic acid Ion clusters Multiple dynamic networks Self-healing strengthening Flexible strain sensor